Specify proxy settings in the program. Example: 
- HTTP works in all browsers except Safari and Firefox
Video guide “How to set up HTTP on a MAC”: - SOCKS5 work only in Safari (all other browsers simply won’t be able to access the Internet, and Firefox will just keep using your original connection, ignoring the proxy. There is a solution for Firefox: the Proxy Toggle extension (as to how to use it, check out the Q&A section)
Video guide “How to set up SOCKS5 on a MAC”:
socks5://username:password@ip:port
Make sure to specify SOCKS5
Step 1. 
Step 2. 
For SOCKS5 - no possible way. For HTTP - currently working on it. Expect a solution in the near future.
Install the Proxy Toggle extension. Link to the extension: https://addons.mozilla.org/ru/firefox/addon/proxy-toggle/. In the extension settings, enter the access data, do not forget to check the Remote DNS checkbox. Example:
The Remote DNS option will automatically replace the DNS GEO from your real one to that of a proxy. For example, you’re in Russia and are using a US proxy without checking the Remote DNS box. Then the GEO of the external IP will be a US one, and the DNS one - a Russian one. Whereas, should you check the mentioned box, both GEOs will be displayed as US.
We do have an API. Contact our Telegram tech support @iproxy_support for instructions on how to work through the API.
In FBTOOL in the Facebook Accounts tab - Add an account. In the proxy settings, type (separated by a colon) ip:port:login:password:socks5
This is what it should end up looking like:
Yes, there is.
Yes, you can. Join our mobile proxy trust sellers.